Asymmetric ACK/NACK Detection for Ultra - Reliable Low - Latency Communications

Abstract

The fifth generation wireless systems are expected to encounter new services in order to provide connectivity for a wide range of applications. One of the considered services is ultra-reliable low-latency communications (URLLC), which has stringent requirements on availability, reliability, and latency. The communication efficiency of URLLC can be improved by employing error control protocols, such as automatic repeat request (ARQ) and hybrid ARQ (HARQ). However, this requires a reliable feedback channel to carry acknowledgement (ACK) and negative ACK (NACK) signals. Improving the detection reliability of ACK and NACK signals simultaneously entails allocating more resources for the feedback channel. Instead, we propose employing an asymmetric signal detection to provide a better protection for NACK signals compared to the ACK signals, without assigning more resources to the feedback channel. The simulation results show that the asymmetric signal detection can achieve a better resource utilization for URLLC.